What is the Jurassic Coast known for?
A number of different mass movement events since 2000
This includes a major landslip 300m long in Lyme Regis in 2008.
What factors contribute to the instability of the cliffs along the Jurassic Coast?
- Wet weather
- Marine processes
- Geological relationship (sandstone on clay)
These factors combine to make the cliffs very unstable.
What is a Mudflow?
A flow of water that carries soil and debris down a slope
Mudflows can occur when heavy rainfall saturates the soil.
What do Rills refer to in the context of runoff water?
Small channels formed by runoff water
Rills are often the initial stage of erosion.
What is a Flow lobe?
A lobe-shaped deposit of mudflow material
Flow lobes indicate the direction of flow in mudflows.
Define Soil Creep.
The slow, gradual movement of soil down a slope
Soil creep can lead to the formation of terracettes.
What are Terracettes?
Small, step-like formations on a slope caused by soil creep
Terracettes are often visible in agricultural fields.
What are Talus Slopes?
Accumulations of rock debris at the base of a cliff
Talus slopes are formed by the weathering and erosion of rocks.
What is Scree or talus?
Debris that accumulates in sheets or cones at the base of slopes
Scree is typically composed of loose rock fragments.
What are Rotational Slumps?
A type of landslide where material moves down a curved surface
Rotational slumps often create scars and terraces on the landscape.
What do scars and terraces indicate?
Evidence of past landslides or soil movement
These features are often associated with rotational slumps.
What are Talus Slopes?
Accumulations of debris, rocks, angular stones, boulders, or gravel at the base of a slope
They typically consist of larger boulders at the core with smaller material on top.
What is the typical angle of rest for Talus Slopes?
34-40 degrees
The angle depends on the size of the fragments; larger fragments result in a steeper angle due to friction between rocks.
True or false: Larger fragments on Talus Slopes lead to a steeper angle of rest.
TRUE
This is due to the increased friction between larger rocks.
What are Rotational Slumps characterized by?
Vegetation layer often remains intact, creating distinctive terraces with bare scar faces between
This results in a formation that resembles a series of steps.
What is the characteristic of block slides regarding debris material?
Debris material tends to stay in larger sizes, often leaves a clean scar above along the failure line (e.g bedding plane)
Block slides are a type of mass wasting event.
What conditions often lead to mudflows?
Mudflows often occur when water is channeled locally to saturate the soil
This saturation creates rills (eroded gullies) and lobes (front edge of deposition).
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1.1 Anthropogenic Coasts11
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1.2 Beach Ready24
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1.3 Historical Discord22
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1.4 Discovering Dalmatia15
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1.5 Raised Beaches16
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1.6 Norwegian Fjords23
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1.7 Relatively Sinking26
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2.1 North Antrim Coast18
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2.2 Piece of Cake26
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2.3 Causeway Complexity21
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2.4 Getting it White21
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2.5 Sharing a platform23
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2.6 Weathering It well7
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2.7 Moeraki Resistance14
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2.8 Mass Movement17
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2.9 Scars and Steps17
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2.10 Guinea Retreat24
